1. Field of the Invention
The present invention relates to an objective replacing apparatus and a microscope using the apparatus. The objective replacing apparatus has a device for detecting an objective replacing operation. When the replacing apparatus, for example a revolver, is moved (rotated) to replace an objective with another, the detection device detects the rotation operation of revolver at rotation start. The microscope automatically controls adjustment of light quantity and adjustment of aperture diameter of aperture diaphragm with the detection device so that the illumination condition is adjusted suitable for a next coming objective being to be set in an optical path of microscope.
2. Related Background Art
There are microscopes provided with an objective replacing apparatus, a light control apparatus, and/or an aperture diaphragm apparatus, which are conventionally arranged as follows. A revolver is known as a conventional objective replacing apparatus. The revolver is held rotatable on a microscope and has a plurality of mount holes concentrically disposed around the rotation center of revolver. An objective is set in each mount hole. The revolver is rotated by an operator in a manual operation or by an automatic mechanism such as a motor, so that an arbitrary objective may be positioned in the optical path of microscope out of a plurality of objectives.
The conventional revolver had a device for detecting an address of each mount hole. There are various devices known for detecting an address of mount hole, for example as disclosed in Japanese Laid-open Utility Model Application No. 56-93713 or in Japanese Laid-open Patent Application No. 62-218915.
Such address detection devices are arranged such that when a desired mount hole is located in the optical path an address of the mount hole is then detected.
Accordingly, the conventional detection devices could not identify during movement of revolver an address of a next coming mount hole being to be set in the optical path, nor an objective set in the mount hole.
Conventional light control apparatuses are arranged such that a photo receptor is located in an observation path of microscope or in a photographic light path of TV camera or the like, that a light quantity of light from a source is detected by the photo receptor, and that the light quantity is adjusted to proper brightness by manually or automatically operating light quantity adjusting means such as a continuously variable ND filter to carry out a light control.
Such light control apparatuses, however, detect a light quantity of light emitted from the source and then passed through an objective, and then adjust the light quantity by operating the ND filter in accordance with the detected light quantity.
When the currently set objective is replaced with another objective having a different magnification by rotating the revolver, light is once shut in the field, because the objective is deviated from the optical path during rotation of revolver. The conventional light control apparatuses respond to this state with a decreased light quantity being detected by the photo receptor so that the ND filter is adjusted to become brighter.
Since brightness is detected after the next objective is located in the optical path and then the ND filter is operated in the conventional light control apparatuses, the apparatuses need a considerable time to obtain a proper light quantity, which interferes smooth observation.
In a microscope provided with such a light control apparatus, excessively bright light suddenly enters the optical path at the moment that the objective enters the optical path, which would cause eye fatigue of observer or which could deteriorate the photo receptor of TV camera. The influence appears great especially when a dark objective is replaced with a bright objective.
In addition, microscopes having an aperture diaphragm in the vicinity of condenser lens are arranged such that a resolution of image by objective, a contrast, a field of depth, and brightness may be adjusted through the aperture diaphragm. In the conventional microscopes an aperture ratio most appropriate to look could be set according to a sort of objective while an observer manually adjusts an opening diameter of aperture diaphragm. A technology was recently developed to automatically adjust the opening diameter of aperture diaphragm.
For example, often used is such an arrangement that the aperture diameter of aperture diaphragm is automatically adjusted in accordance with an objective set in a mount hole located at a stop position of revolver, using the aforementioned address detection device of mount hole in revolver.
The automatic adjusting device, however, starts the adjusting operation to optimize the opening diameter of aperture diaphragm after the revolver is stopped. Accordingly, the conventional microscopes permit no observation before the diameter of aperture diaphragm is adjusted, providing a problem of waiting time.